<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
	<script>
		'use strict'

		console.log('a\'');//转义
		console.log("a");

		let name = 'shelly';
		let age = 5;
		let msg = `你好啊，${name},我年龄${age}岁了`;
		console.log(msg);

		//大小写转换
		let stu = "student";
		stu.toUpperCase();// 大写设置
		stu.toLowerCase();// 小写设置

		//显示下标
		stu.indexOf('u');//显示3
		stu.indexOf('s');//显示0

		//字符串截取
		stu.substring(1,3);// 显示tu

	</script>
</head>
<body>

</body>
</html>